Engine starting system



Feb. 16, 1937. K. F. DOUGLAS 2,071,028

ENGINE STARTING SYSTEM Filed Nov. 7, 1934 2 Sheets-Sheet l [1V VENTOR WQVDW Feb. 16, 1937; K. F. DOUGLAS, 2,071,028

ENGINE STARTING SYSTEM Filed Nov. 7, 1954 2 Sheets-Sheet 2 g i w Mum 5i l/VVENTO/f Milt/L985: W/b%l?0uglas TORNEY Patented Feta-16, 1 937- UNITED STATES PATENT OFFICE ENGINE STARTING SYSTEM Application November 7, 1934, Serial No. 751,846

6 Claims.

The present invention relates to an engine starting system and more particularly to a switching mechanism for controlling the energization of an electrical starter for internal combustion en- In certain starting installations, particularly those used to start large engines such as commercial and marine Diesel power plants, it has been found desirable to delay the application of the full battery voltage to the starting motor until after the driving connection from the motor to the engine has been substantially or fully established. In this manner, the engagement of the drive takes place more quietly and without unnecessary strain on the working parts.

y In arrangements of this character, it is preferable to have a. time delay between the closing of the initial circuit and the application of full voltage to the starting motor in order to insure prior engagement of the drive. It is also desirable that the main starting switch be operated electrically in order that the closing pressure thereof shall be uniform and the release rapid, thus avoiding arcing and welding of the contacts.

It is an object of the present invention to provide a novel engine starter control for gradually applying the cranking torque to the engine to be started.

It is another object to provide such a device embodying drive gearing for automatically connecting the motor to the engine to be started, in which the starting motor is initially actuated at a comparatively low effective voltage in order to engage the drive, and thereafter the full cranking voltage is applied to the motor.

It is a further object to provide such a device which includes structure for securing a time delay after initial actuation of the starting motor before the full battery voltage is applied thereto.

Further objects and advantages will be apparent from the following description taken in connection with the accompanying drawings in which:

Fig. 1 shows semi-diagrammatically one preferred embodiment of the invention, the parts being shown in normal or idle position;

Fig. 2 is a diagrammatic view of the same showing the parts in the positions assumed during the establishment of the drive from the starting motor to the engine to be started;

Fig. 3 is a view similar to Fig. 2 showing the parts in cranking position; and

Fig. 4 is a semi-diagrammatic illustration of a second embodiment of the invention.

Referring first to Fig. 1 of the drawings, there is illustrated an electrical starting system for an internal combustion engine including a battery I grounded at 2 and a starting motor SM grounded at 3 arranged to be operated thereby. It will be understood that any usual form of automatic 5 gear drive is used to connect the motor to crank the engine, such for instance as illustrated in Fig. 4.

Two parallel circuits between the battery I and the starting motor are provided, one for securing 10 engagement of the drive by partial energization of the starting motor, the other being arranged to apply the full voltage of the battery to the starting motor for cranking the engine. The firstmentioned circuit includes lead I, manual-magl5 netic switch 5, lead 6, resistor element I and lead 8. Resistor element I is of such value that when the switch 5 is closed, the starting motor will be energized only sumciently to cause engagement of the starting mechanism. The second circuit 20 includes lead 9, magnetic switch II and lead I2 whereby closure of the switch II connects the battery directly to the starting motor, causing energization thereof by the full battery voltage in order to crank the engine. 3

Switch 5 is provided with an electromagnetic holding coil I3 which is connected to the lead 6 by a lead I4 and is connected to the motor lead I2 by a lead I5, whereby the coil I3 is in shunt with the resistor I and is energized by the voltage drop through said resistor when switch 5 is closed, thereby holding said switch closed. Magnetic switch I I comprises an electromagnetic coil I6 which may be connected to the battery through a lead II, manually operated switch III, 35 lead I9, lead 2I and spring-mounted contact 22 which is arranged to be engaged by the bridging element 23 of switch 5 when said switch closes, the battery connection then being completed through the lead 4. An alternative connection 40 for the coil I6 from lead I9 is provided through lead 24 and contact 25 which is adapted to be engaged by contact 26 yieldably mounted on the movable member 21 of magnetic switch II, the battery connection then being completed through 4,5 the lead 9. The coil I6 is grounded through an engine-driven generator G to complete the battery circuit therethrough when the engine is idle, said generator being arranged to prevent the flow of current through coil I6 when the engine is self-operative.

Manual operating means for the switch I8 is provided in the form of a button 28 mounted on a post 29 which is arranged as illustrated adjacent to the end of the plunger 3| of switch I ll whereby depression of the button 28 first opens switch I8 and then causes closure of switch 5 as illustrated in Fig. 2.

In the operation of this embodiment of the invention, starting with the parts in the positions illustrated in Fig. l, depression of the button 28 by the operator first opens switch l8, thereby preventing energization of coil l6 of magnetic switch II, and upon further depression thereof closes switch 5, thus completing the initial low voltage circuit through the starting motor as illustrated in Fig. 2. The starting motor is thereby energized sufficiently to cause engagement of the starter drive with the engine without undue shock, but insufllciently to institute the cranking operation. Contact 22 is engaged by switch member 23, but since manual switch I8 is open at this time, the coil I6 is not energized. Coil I3 of switch 5 is energized by the voltage drop across the resistor I which is substantially the full battery voltage, since at this time the starting motor is stalled by its engagement with the engine, whereby coil 3 holds switch 5 closed.

In order to institute the cranking operation, the operator thereupon releases the button 28, permitting closure of switch 8. Since the switch 5 is held closed by the coil I3, a circuit is established through contact 22, leads 2| and I9, switch l8 and lead whereby coil I6 is energized to close the magnetic switch The closing movement of switch first closes contacts 26, 25, thereby establishing the additional battery connection for coil [6 through lead 24, contacts 25, 28, switch member 21, and lead 8. Thereafter, closure of the main contacts in switch causes full battery voltage to be applied to the starting motor to cause it to crank the engine. Closure of switch short-circuits the resistor 1 and the coil I3 of switch 5 whereby coil I3 is deenergized, permitting switch 5 to open. Contact 22 is thus disconnected from the battery, but the connection through the contacts 25, 26 maintains coil l8 of switch energized whereby cranking is not interrupted.

When the engine starts, the generator G, driven thereby, builds up a voltage which opposes the passage of battery current through coil Hi, thereby deenergizing said coil and permitting the magnetic switch H to open, whereby the parts are restored to their original positions as shown in Fig. 1.

Should the engine fail to start for any reason, the cranking operation may be interrupted by the operator by merely depressing the button 28 sutficiently to open switch l8. Coil l8 of switch H is thereby deenergized and the parts restored to normal position.

It will be understood that the time delay between the initial actuation of the starting motor to secure engagement of the gearing and full actuation thereof for cranking purposes-is here secured by the necessity for the operator to first depress the button 28 to secure the engagement of the drive and then release said button to secure cranking. Since the engagement of the starter drive takes place in a very small fraction of a second, it is obvious that this time delay is ample to insure such engagement prior to application of the full voltage of the battery for cranking purposes.

In the embodiment of the invention shown in Fig. 4, this time delay is secured automatically by the operation of the starter drive itself. As there shown, a circuit for securing engagement of the drive by partial energization of the motor is provided including a lead 32, a manual switch 33, lead 34, resistor element 35 and lead 3|i. A cranking connection for applying full battery voltage to the motor is provided in the form of a lead 31, a magnetic switch 38 and lead 39. Magnetic switch 38 includes an electromagnetic 'coil 4| connected to the lead 34 of manual switch 33 by alead 42, and connected by a lead 43 to an insulated contact 44 which is arranged to be automatically grounded when the starter drive is in engagement with the engine member.

As here illustrated, contact 44 is. for this purpose mounted on the starting motor housing 45', suitably insulated therefrom, which housing supports in the usual manner a conventional type of starter drive including screw shaft 46 adapted to be driven by the starting motor, carrying a pinion 41 threaded thereon for movement into and out of driving engagement with a member such as a flywheel gear 48 of the engine to be started. According to the present invention, the pinion 41 is provided with a tapered flange 48, and a plunger 5| is slidably mounted in the housing 45 in position to be engaged by said flange and to be'projected upwardly thereby when the drive pinion meshes with the engine gear. A grounding contact 52 is spring mounted adjacent contact 44, normally out of engagement therewith, and plunger 5| is arranged to engage and move contact 52 into engagement with contact 44 and ground-the same when the drive pinion is moved to operative position.

There is a tendency in starter drives of this character for the pinion to reciprocate longitudinally to some extent as the engine passes over its compression points, and such longitudinal movement of the pinion might cause contacts 52, 44 to open, thus interrupting the cranking. Means to prevent such interruption of the cranking operation is therefore provided in the form of a resistance element 53 connecting contacts 44, 52, said resistance being-of such value as to permit suflicient current to traverse the coil 4| to retain switch 38 in closed position by preventing passage of sufficient current to cause closure of said switch.

In the operation of this embodiment of the invention, closure of manual switch 33 by the operator closes the low voltage circuit through resistor 35 to the starting motor, thereby causing engagement of the drive in the usual manner. A circuit is also established thereby through lead 42, coil 4|, lead 43, resistance 53 to the ground on the motor housing, but since the resistance 53 prevents full energization of coil 4 magnetic switch 38 remains open. The movement of the pinion 4! into its driving position as illustrated in dotted lines raises plunger 5|, thus closing contacts 44, 52 and causing full energization of coil 4| to close the magnetic switch 38. Closure of switch 38 causes the full battery voltage to be applied to the starting motor, whereupon cranking takes place as usual.

Should the pinion 4'! shuttle back and forth slightly during the cranking operation as the engine goes over its compression points, contacts 44, 52 may be caused to vibrate, but cranking is not interrupted thereby since resistance element 53 permits suflicient current to traverse the coil 4| to hold the switch 38 closed. When the engine starts, or if the engine should fail to start, release of themanual switch 33 opens the cranking circuit and deener glzes thestartingmotor.

It will be appreciated that in this embodiment of the invention the time delay for, insuring engagement of the drive prior to full energization of the starting motor is automatically provided by the operation of the drive itself so that premature application of the full battery voltage to the motor is prevented.

Although but two embodiments of the invention have been shown and described in detail, it will be understood that other embodiments are possible and that various changes may be made in the details and arrangements of the parts without departing from the spirit of the invention as defined in the claims appended hereto.

What is claimed is:

1. In combination with an internal combustion engine, a starting system therefor including a battery, a motor, means including a manually operable switch for initially energizing the motor by a part of the battery voltage, manually controlled means for applying full battery voltage to the motor, means responsive to the application of full battery voltage to the motor for opening said manually operable switch, and means responsive'to self-operation of the engine for deenergizing said manually controlled means.

2. In combination with an internal combustion engine, a starting system therefor including a battery, a motor, means including a manually operable switch for initially energizing the motor by a part or the battery voltage, means for holding closed'said manually operable switch, means for applying full battery voltage to the motor, means whereby the application of full battery voltage to the motor deenergizes the holding means for the manually operable switch, and means responsive to self-operation of the engine for deenergizing said means for applying full battery voltage to said motor.

3. In combination with an internal combustion engine, a starting system therefor including a battery, a motor, means including a switch for initially energizing the motor by a part of the battery voltage, manual means for closing said switch, means for holding said switch closed, means for applying full battery voltage to the motor, means whereby the application of full battery voltage to the motor deenergizes the 'holding means for the switch, means responsive to self-operation of the engine for deenergizing said means for applying full battery voltage to said motor, and means operable by said manual means for deenergizing said motor in case the engine fails to start.

4. In combination with an internal combustion engine, a starting system therefor including a battery and a motor, a normally closed switch and a normally open switch, manual means operable flrst to open the normally closed switch and thereafter to close said normally open switch,

means whereby closure of the normally open switch causes energization of the motor with a part of the eflective battery voltage, means whereby subsequent closure of the normally closed switch causes the full battery voltage to be applied to the motor, means for opening said normally open switch responsive to full energization of the motor, and means responsive to selfoperation of the engine for deenergizing the motor,

5. In combination with an internal combustion engine, a starting system therefor including a battery and a motor, a normally closed switch and a normally open switch, manual means operable first to open the normally closed switch and thereafter to close said normally open switch, means whereby closure of the normally open switch causes energization of the motor with a part of the effective battery voltage, electromagnetic means energized by closure of the normally open switch for holding said switch closed, an electromagnetic switch for applying full battery voltage to the motor, and means for energizing said electromagnetic switch including two sets of normally open contacts in parallel, one set being closed by closure of the normally open switch and the other set being closed by closure of the electromagnetic switch, said normally closed switch being in series with both said sets of contacts.

6. In combination with an internal combustion engine, a starting system therefor including a battery and a motor, a normally closed switch and a normally open switch, manual means operable first to open the normally closed switch and thereafter to close said normally open switch, means whereby closure of the normally open switch causes energization of the motor with a part of the eii'ective battery voltage, electromagnetic means energized by closure of the normally open switch for holding said switch closed, an electromagnetic switch for applying full battery voltage to the motor and at the same time bridging out said holding means, means for energizing said electromagnetic switch including two sets of normally open contacts in parallel, one set being closed by closure of the normally open switch, and the other set being closed by closure of the electromagnetic switch, said normally closed switch being in series with both said sets of contacts, and an engine-driven generator arranged'to deenergize said electromagnetic switch responsive to self-operation of the engine.

KENNETH F. DOUGLAS. 

